<?php

/**
 * MemCached缓存.
 *
 * [WeEngine System] Copyright (c) 2014 W7.CC
 */
defined('IN_IA') or exit('Access Denied');

function cache_memcache() {
    global $_W;
    static $memcacheobj;
    if (!extension_loaded('memcache')) {
        return error(1, 'Class Memcache is not found');
    }
    if (empty($memcacheobj)) {
        $config = $_W['config']['setting']['memcache'];
        $memcacheobj = new Memcache();
        if ($config['pconnect']) {
            $connect = $memcacheobj->pconnect($config['server'], $config['port']);
        } else {
            $connect = $memcacheobj->connect($config['server'], $config['port']);
        }
        if (!$connect) {
            return error(-1, 'Memcache is not in work');
        }
    }

    return $memcacheobj;
}

/**
 * 取出缓存的单条数据.
 *
 * @param 缓存键名 ，多个层级或分组请使用:隔开
 *
 * @return mixed
 */
function cache_read($key, $forcecache = true) {
    $key = cache_namespace($key);

    $memcache = cache_memcache();
    if (is_error($memcache)) {
        return $memcache;
    }
    $result = $memcache->get(cache_prefix($key));
    if (empty($result) && empty($forcecache)) {
        $dbcache = pdo_get('core_cache', array('key' => $key), array('value'));
        if (!empty($dbcache['value'])) {
            $result = iunserializer($dbcache['value']);
            $memcache->set(cache_prefix($key), $result);
        }
    }

    return $result;
}

/**
 * 检索缓存中指定层级或分组的所有缓存.
 *
 * @param 缓存分组
 *
 * @return mixed
 */
function cache_search($key) {
    return cache_read(cache_prefix($key));
}

/**
 * 将值序列化并写入缓存.
 *
 * @param string $key
 * @param mixed $value
 * @param int $ttl
 * @return mixed
 */
function cache_write($key, $value, $ttl = 0, $forcecache = true) {
    $key = cache_namespace($key);
    $memcache = cache_memcache();
    if (is_error($memcache)) {
        return $memcache;
    }
    if (empty($forcecache)) {
        $record = array();
        $record['key'] = $key;
        $record['value'] = iserializer($value);
        pdo_insert('core_cache', $record, true);
    }
    if ($memcache->set(cache_prefix($key), $value, MEMCACHE_COMPRESSED, $ttl)) {
        return true;
    } else {
        return false;
    }
}

/**
 * 删除某个键的缓存数据.
 *
 * @param string $key
 *
 * @return mixed
 */
function cache_delete($key, $forcecache = true) {
    $memcache = cache_memcache();
    if (is_error($memcache)) {
        return $memcache;
    }
    $cache_relation_keys = cache_relation_keys($key);
    if (is_error($cache_relation_keys)) {
        return $cache_relation_keys;
    }
    if (is_array($cache_relation_keys) && !empty($cache_relation_keys)) {
        foreach ($cache_relation_keys as $key) {
            $cache_info = cache_load($key);
            if (!empty($cache_info)) {
                $origins_cache_key = $key;
                $key = cache_namespace($key);
                if (empty($forcecache)) {
                    pdo_delete('core_cache', array('key' => $key));
                }
                $result = $memcache->delete(cache_prefix($key));
                unset($GLOBALS['_W']['cache'][$origins_cache_key]);
                if (!$result) {
                    return error(1, '缓存: ' . $key . ' 删除失败！');
                }
            }
        }
    }

    return true;
}

/**
 * 清空缓存指定前缀或所有数据.
 *
 * @param string $prefix
 */
function cache_clean($prefix = '') {
    if (!empty($prefix)) {
        $cache_relation_keys = cache_relation_keys($prefix);
        if (is_error($cache_relation_keys)) {
            return $cache_relation_keys;
        }
        if (is_array($cache_relation_keys) && !empty($cache_relation_keys)) {
            foreach ($cache_relation_keys as $key) {
                preg_match_all('/\:([a-zA-Z0-9\-\_]+)/', $key, $matches);
                $cache_namespace = cache_namespace('we7:' . $matches[1][0]);
                pdo_delete('core_cache', array('key LIKE' => $cache_namespace . '%'));
                unset($GLOBALS['_W']['cache']);
                cache_namespace('we7:' . $matches[1][0], true);
            }
        }

        return true;
    }
    $memcache = cache_memcache();
    if (is_error($memcache)) {
        return $memcache;
    }
    if ($memcache->flush()) {
        unset($GLOBALS['_W']['cache']);
        pdo_delete('core_cache');

        return true;
    } else {
        return false;
    }
}

/**
 * Memcache不支持命名空间，自己实现一个
 * 将key中第一段的值做为命名空间，方便按前缀删除（系统有自己的前缀所以以第一，第二段）.
 *
 * @param string $key
 *
 * @return mixed
 */
function cache_namespace($key, $forcenew = false) {
    if (!strexists($key, ':')) {
        $namespace_cache_key = $key;
    } else {
        list($key1, $key2) = explode(':', $key);
        if ('we7' == $key1) {
            $namespace_cache_key = $key2;
        } else {
            $namespace_cache_key = $key1;
        }
    }
    if (!in_array($namespace_cache_key, array('unimodules', 'user_modules', 'system_frame'))) {
        return $key;
    }

    //获取命名空间
    $namespace_cache_key = 'cachensl:' . $namespace_cache_key;
    $memcache = cache_memcache();
    if (is_error($memcache)) {
        return $memcache;
    }
    $namespace = $memcache->get(cache_prefix($namespace_cache_key));
    if (empty($namespace) || $forcenew) {
        $namespace = random(5);
        $memcache->set(cache_prefix($namespace_cache_key), $namespace, MEMCACHE_COMPRESSED, 0);
    }

    return $namespace . ':' . $key;
}

function cache_prefix($key) {
    return $GLOBALS['_W']['config']['setting']['authkey'] . $key;
}
